Rolling diaphragm construction

ABSTRACT

The disclosure relates to a diaphragm sleeve which is rolled inside out in a tank by a motive fluid supplied to one side thereof to positively displace fluid at the opposite side of the diaphragm from the tank. At least one supporting ring engages either the inner or outer periphery of the sleeve to resist lateral buckling of the sleeve and which slides along the sleeve as the latter rolls inside out.

atertt H :1 1 1 in [H] Grossman Nov. 12., WM

[ ROLLHNG DIIAPHRAGM CUNSTREUQTEUN 2,798,639 7/1957 Urban 222/386.5 x

2,924,359 2/1960 Ber maid... 222/386.5 [75] lnvemor' Walter Grlssmani Law, 3,112,845 12/1963 Bryznt ZZZ/386.5 X 3,158,296 11/1964 Cornelius 222/3865 [73] Assignee: Thiokoi Chemical Corporation,

Bristol, Pa. Primary Examiner-Verlin R. Pendegrass [22] Filed: "Oct. 10, 1966 211 App]. No.: 536,599 [57] ABSTRA'CT The disclosure relates to a diaphragm sleeve which is rolled inside out in a tank by a motive fluid supplied to one side thereof to positively displace fluid at the op- [58] Fie'ld 158/50 posite side of the diaphragm from the tank. At least 239/3'23 one supporting ring engages either the inner or outer periphery of the sleeve to resist lateral buckling of the [56] References CHM sleeve and which slides along the sleeve as the latter ll "d t, UNITED STATES PATENTS m g e 2,009,761 7/1935 Calderara 222 95 H Ciaims, 3 Drawing Figures PATENTEUHUV 12 I91 3.847139 sum 2 or 2 INVENTOR.

WALTER B. GROSSMAN ATTORNEYS lliGlLlLlNG DlAPlhlRAGli/il CGNSTlklUCTllGN This invention relates generally to positive displacement, liquid expulsion systems in which a diaphragm is attached to the liquid containing tank and to a piston therein which is propelled by gas pressure through the tank to expel the liquid, and relates more particularly to an improved, reinforced diaphragm for such use and various other applications.

Diaphragms of this general type are particularly useful in the liquid propellant expulsion systems of packaged liquid rocket engines but their usefulness has been limited in that their flexibility decreases as their size (and gauge) increases to accommodate greater propellant volumes.

Analytical and experimental work has shown that the cylindrical length of the diaphragm is limited by the fact that the same pressure which acts on the piston, also acts laterally'on the cylinder. in order to avoid buckling of the cylindrical diaphragm, the pressure which produces the piston movement must be less than the critical buckling pressure of the cylinder.

Accordingly, the main object of the present invention is to provide an improved diaphragm construction which permits the use of a cylindrical diaphragm of increased length in an expulsion system and hence enables an increased propellant or liquid volume which may be stored and expelled.

An important object of the present invention is to 7 provide an improved diaphragm of the type described which is provided with reinforcing means to resist buckling of the cylindrical diaphragm during expulsion of the liquid. 7

Another importantobject of the present invention is to provide a hermetically sealed, rolling metal diaphragm for piston propellant expulsion in package liquid-rocket engines in which resistance to cylindrical di aphragm buckling is provided by wires positioned at spaced points in peripheral contact with the dia phragm.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the drawings, several embodiments of the invention'are shown. in these showings:

lFiG. i is a fragmentary, central, longitudinal sectional view of a liquid expulsion apparatus in the storage position showing the tank for the liquid to be expelled, the expelling piston, the cylindrical diaphragm hermetically sealed to both the piston and the tank, and the reinforcing means for the diaphragm;

FiG. 2-6) are fragmentary, sectional views of the different forms of the reinforcing means;

PEG. '7 is a view similar to i and showing means for moving the reinforcing means toward the expulsion Y end of the tank during expulsion; and

PEG. h is a view similar to lFiG. 7 but showing the dia phragm completely rolled back and the reinforcing means collected and compressed thereby at the discharge end of the tank.

Referring to the drawings, numeral id designates a liquid expulsion apparatus as a whole which comprises a cylindricaltank t2, a piston Ml, a diaphragm to, and one form of reinforcing means 117.

The tank T2 is provided with ends (hernispherically shaped as shown) id and 2t) and intermediate its length, one end of the cylindrical diaphragm To is her metically sealed thereto as at 22. The tank end is is provided with an inlet M for the admission of a gas or other pressurizing medium into the tank to act on the piston 114i and force it through the tank to abut the other end wall 20. The liquid filling the tank to the right of the piston is expelled through a discharge port as which may be provided with a burst disc. etc. 2%.

The piston M to which the other end of the cylindrical diaphragm is hermetically sealed, may be formed of aluminum or other lightweight metal and is shaped (hemispherical as shown) to conform with the shape of the tank ends lid and 2th to afford a maximum of volumetric and expulsion efficiency.

The diaphragm llti comprises a cylindrical shell in which sufficient resistance to buckling by the lateral and radial pressures of the pressurizing medium, is provided by reinforcing means provided at spaced points along the length of the cylindrical diaphragm lie and designated by numeral 17 in FllG. i, which comprises rings circular in cross-section which engage the inner surface of the diaphragm and mechanically strengthen it against the buckling pressure of the pressurizing medium.

it will be appreciated that the reinforcing rings may be positioned exteriorly of the diaphragm to as shown in FIG. 2 wherein reinforcing ring .34 is fixed to the diaphragm by welding, glue, etc. 36, and that the rings 34 may be only partially exterior of the diaphragm by being fixed to a circular indentation 38 formed in the diaphragm as shown in Fit]. 3, Similarly, as shown in FIG. d, the rings 34 may be positioned so as to engage the inner surface 40 of ribs formed in the diaphragm.

tially the same. Pressure fluid from a suitable source is admitted to the tank 112 by way of the inlet port 24 to act against the liquid expelling piston lid and move it to the right to expel the liquid in the tank through the discharge port 26 when the built-up pressure bursts the disc 2%.

As the piston id moves to the right toward the tank end 2t) expelling the liquid in the tank, the thin flexible diaphragm lid which acts as a seal between the pressurizing medium and the liquid is rolled backwardly toward the right and the reinforcing rings if exterior and fixed move along therewith and if interior and not fixed, will move with the involution of the cylindrical diaphragm as it moves toward the expulsionend of the tank with the piston Ed until the piston assumes the position shown in FllG. h at the completion of liquid expulsion.

The disclosure of FIGS. '7 and d embodies the same principle of the invention as set forth above but employs a helical spring 45 which is preferably made of wire of any desired cross-section, and is fixed to the interior of the diaphragm M. Alternatively, it may be fixed to the exterior of the diaphragm as suggested in H03. 2 and 3 or merely engage: the interior as suggested in FIG. tl.

In the form of the invention shown in FIGS.;7 and 8, the diaphragm 16 is provided adjacent the piston M with a series of radially disposed inwardly projecting circumferentially spaced pins 46. During operation of this form of the invention, as pins in the cylindrical dia- .phragm 16 traverse the involution, they come in helical spring becomes fully compressed.

It will be appreciated that the rings of FIGS. 1, 4, and 6 may be substituted for the helical spring 45 at the substantially uniformly spaced intervals disclosed and that during the liquid expulsion stroke of the piston 14,

the pins 46 contact each ring, in turn, and push it to-- ward the discharge port or outlet of the tank so that at the end of the pistons liquid expulsion stroke, the rings also are in contact with each other as shown in FIG. 8.

As the diaphragm'lo rolls back on itself, its diameter must decrease so that the inner fold or layer can slide by the original outer layer or wall. This reduction in diameter takes place automatically with a corresponding change in the wall thickness and/or elongation of the diaphragmzwhen the rings 17, 34, 42 or 45, either individually as; in FIG. 1 or as coils of a continuous spring asin FIG. 7, are attached to the diaphragm they have substantially the same thickness as the diaphragm wall and'act in the same manner as the diaphragm. In other words, the rings will flow through the other rings by a reduction in diameter with a flow of the material to produce a greater cross sectional area at a smaller ring diameter.

It is to be understood that the forms of the invention herewith shown and described are to be taken as preferred examples of the same and that various changes in the shape, size and arrangement of parts may be resorted to without departure from the spirit of the invention or the scope of the subjoined claims.

What is claimed is:

1. The combination with a liquid expulsion tank having a piston movable therein by a pressurizing medium from one end of the tank to the other to expel the liquid therefrom; of a flexible diaphragm having a continuous wall hermetically sealed at its ends to the peripheral wall of the tank and to the outer periphery of the movable piston, said diaphragm being rollable backwardly within itself by said piston upon liquid expelling movement thereof, and reinforcing means engaging said diaphragm along its length to strengthen it against buckling by the pressurizing medium acting on the piston comprising at least one transversely disposed ring engaging a periphery of said diaphragm and slidable along said diaphragm as the latter is turned inside out.

2. The combination recited in claim I wherein said reinforcing means comprises at least one transversely disposed ring engaging the inner periphery of said diaphragm and slidable along the diaphragm.

'3. The combination recited in claim 2 wherein said reinforcing means comprises a plurality of rings engaging said cylindrical diaphragm at'spaced points along its length, and each ring being circular in cross-section.

4. The combination recited in claim 2 wherein said rings are rectangular in, cross-section.

5. The combination recited in claim I wherein said diaphragm is a metallic sleeve and said reinforcing means comprises transversely disposed metal rings attached to the outer periphery of said diaphragm and adapted to turn from the exterior to the interior of said diaphragm sleeve as the latter turns inside out.

6. The combination recited in claim I wherein said reinforcing means comprises a helical spring having its individual coils engaging the inner periphery of said diaphragm at spaced locations and slidable therealong at it rolls along the tank. 7. The combination recited in claim 2, and means projecting from the periphery of said diaphragm adjacent the piston and rollableback therewith to engage said rings and move them toward the other end of the tank. 5 v

8. The combination recited in claim 6, and means projecting from the periphery of said diaphragm adja cent the piston and engageable with said spring to compress it upon rolling back movement of said diaphragm.

9. The combination recited in claim 1 wherein said diaphragm is a metallic sleeve and said reinforcing means comprises a helical metallic spring having its coils attached to the outer periphery of said diaphragm adapted to turn from the outer periphery to the inner periphery of the diaphragm as the latter turns inside out.

10. The combination with a liquid expulsion tank having a piston movable therein by a pressurizing medium from one end of the tank to the other to expel the liquid therefrom; of a flexible cylindrical diaphragm hermetically sealed at its ends to the inner periphery of the tank and to the outer periphery of the movable piston, said diaphragm being rollable backwardly within itself by said piston upon liquid expelling movement thereof and said cylindrical diaphragm including circular indentations at spaced points along its length, and reinforcing rings attached to said indentations to strengthen said diaphragm against buckling by the pressurizing medium.

11. The combination recited in claim 10 wherein said diaphragm has circular ribs at spaced points along its length, and said reinforcing rings engaging. the inner periphery of said ribs to strengthen said diaphragm against buckling by the pressurizing medium. 

1. The combination with a liquid expulsion tank having a piston movable therein by a pressurizing medium from one end of the tank to the other to expel the liquid therefrom; of a flexible diaphragm having a continuous wall hermetically sealed at its ends to the peripheral wall of the tank and to the outer periphery of the movable piston, said diaphragm being rollable backwardly within itself by said piston upon liquid expelling movement thereof, and reinforcing means engaging said diaphragm along its length to strengthen it against buckling by the pressurizing medium acting on the piston comprising at least one transversely disposed ring engaging a periphery of said diaphragm and slidable along said diaphragm as the latter is turned inside out.
 2. The combination recited in claim 1 wherein said reinforcing means comprises at least one transversely disposed ring engaging the inner periphery of said diaphragm and slidable along the diaphragm.
 3. The combination recited in claim 2 wherein said reinforcing means comprises a plurality of rings engaging said cylindrical diaphragm at spaced points along its length, and each ring being circular in cross-section.
 4. The combination recited in claim 2 wherein said rings are rectangular in cross-section.
 5. The combination recited in claim 1 wherein said diaphragm is a metallic sleeve and said reinforcing means comprises transversely disposed metal rings attached to the outer periphery of said diaphragm and adapted to turn from the exterior to the interior of said diaphragm sleeve as the latter turns inside out.
 6. The combination recited in claim 1 wherein said reinforcing means comprises a helical spring having its individual coils engaging the inner periphery of said diaphragm at spaced locations and slidable therealong at it rolls along the tank.
 7. The combination recited in claim 2, and means projecting from the periphery of said diaphragm adjacent the piston and rollable back therewith to engage said rings and move them toward the other end of the tank.
 8. The combination recited in claim 6, and means projecting from the periphery of said diaphragm adjacent the piston and engageable with said spring to compress it upon rolling baCk movement of said diaphragm.
 9. The combination recited in claim 1 wherein said diaphragm is a metallic sleeve and said reinforcing means comprises a helical metallic spring having its coils attached to the outer periphery of said diaphragm adapted to turn from the outer periphery to the inner periphery of the diaphragm as the latter turns inside out.
 10. The combination with a liquid expulsion tank having a piston movable therein by a pressurizing medium from one end of the tank to the other to expel the liquid therefrom; of a flexible cylindrical diaphragm hermetically sealed at its ends to the inner periphery of the tank and to the outer periphery of the movable piston, said diaphragm being rollable backwardly within itself by said piston upon liquid expelling movement thereof and said cylindrical diaphragm including circular indentations at spaced points along its length, and reinforcing rings attached to said indentations to strengthen said diaphragm against buckling by the pressurizing medium.
 11. The combination recited in claim 10 wherein said diaphragm has circular ribs at spaced points along its length, and said reinforcing rings engaging the inner periphery of said ribs to strengthen said diaphragm against buckling by the pressurizing medium. 